[991] Stage II-IV Low-Grade Serous Carcinoma of the Ovary: A Clinicopathological Study of 33 Patients.

Rola H Ali, Steve E Kalloger, Jennifer L Santos, Kenneth D Swenerton, Blake Gilks. Vancouver General Hospital, BC, Canada; British Columbia Cancer Agency, Vancouver, Canada

Background: Low-grade serous carcinoma of the ovary has only recently been recognized as a disease entity distinct from the more common high-grade serous carcinoma. When confined to the ovary, low grade serous carcinoma is associated with a very favorable prognosis and chemotherapy is typically not recommended. There is little information on the prognosis of patients with low-grade serous carcinoma who have extra-ovarian spread at presentation.
Design: Thirty-three cases of stage II-IV ovarian low-grade serous carcinoma were identified in the Cheryl Brown Ovarian Cancer Outcomes Unit. In 19 cases blocks were available and immunostaining for Ki-67, WT1, E-cadherin, p16, and p53 was performed. Comparison of expression of these markers in low-grade serous carcinoma we made with data on the same immunomarkers in a series of >400 cases of high-grade serous carcinoma.
Results: Mean age of the patients was 56 years. The tumors presented at stage II in 10/32 cases, stage III in 21/32 cases, and stage IV in 1/32 case. On follow up, most patients died of disease, with less than 30% survival at 10 years. Compared to high-grade serous carcinomas, the low-grade serous carcinomas were significantly more likely to express p16 at high levels, and to show abnormal p53 expression (p=0.004 and p<0.0001, respectively). Ki-67 staining indices were lower in the low-grade serous carcinomas than the high-grade serous carcinomas (p<0.0001). There were no significant differences between low-grade serous carcinomas and high-grade serous carcinomas with respect to expression of WT1 and E-cadherin (p=0.81 and p=0.19, respectively).
Conclusions: This group of patients with low-grade serous carcinoma who had extraovarian spread at the time of presentation had an unfavorable prognosis, similar to that of patients with high-grade serous carcinoma. The immunoprofile of these cases was similar to what has previously been reported for low-grade serous carcinoma, with evidence of lower tumor proliferation and fewer p53 abnormalities than are seen in high-grade serous carcinoma.
Category: Gynecologic & Obstetrics

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 99, Tuesday Afternoon

 

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